Counterweighted crank



Oct. 22, 1940. J c SLQNNEGER 2,219,080

COUNTERWEIGHTED CRANK Filed Jan. 6, 1936 INVENTOR. LjbHN 5.E'LUJVNE'EE'R ATTORNEY.

Patented Oct. 22, 1940 UNITED STATES PATENT OFFICE COUNTERWEIGHTED CRANKtion of Wisconsin Application January 6, 1936, Serial No. 57,689

4. Claims.

This invention relates to counterweighted cranks for driving oil wellpumps and like equipment.

An oil well pumping apparatus ordinarily includes a long string of pumprods which lead to the bottom of the well and which are supported fromand reciprocated by one end of a walking beam arranged at the head ofthe well. The walking beam is commonly actuated by a power driven rotarycrank connected to the other end thereof through a wrist pin and pitman.

It is common practice to regulate the stroke of the pump by regulatingthe effective length of the crank, this being accomplished ordinarily byshifting the wrist pin from one to another of a plurality of holesprovided in the crank at variable distances from the axis of rotation ofthe crank. The necessary size of the holes and the required spacingbetween them is such that the number of holes and consequently thenumber of pin positions is very limited, thus rendering it impossible toeffect a fine adjustment of the pump stroke.

25 It is also quite common practice to fix counterweights to the end ofthe crank in an effort to smooth out the torque load imposed upon thecrank shaft by the fluctuating load transmitted from the pump, and theeffect of the counterweights upon the system is disturbed whenever thewrist pin is adjusted to vary the effective length of the crank. Tocompensate for this, it is ordinarily necessary to independently adjustthe size or position of the counterweights whenever the position of thewrist pin is changed.

One object of the present invention is to provide a counterweightedcrank for the purposes mentioned in which the position of thecounterweights will automatically change to compensate for changes ineffective length of the crank.

Another object is to provide a counterweighted crank for the purposesmentioned so constructed as to facilitate adjustment of its effectivelength.

Another object is to provide a counterweighted crank for the purposesmentioned so constructed as to provide a finer adjustment of cranklength than is possible with cranks now in use.

Other objects and advantages will appear, expressed or implied, from thefollowing description of a counterweighted crank constructed inaccordance with the present invention. In the accompanying drawing: Fig.1 is an elevation of a counterweighted 55 crank embodying the presentinvention.

thereof adjacent the end of the opening H. T

pin I4 projects from the face of the crank in position to receive theusual pitman through which it is connected to the usual walking beam .ina well known manner.

In this instance, the formation I3 i dished or hollowed out, asindicated at IE, to receive and partially house a number of plates [6which constitutecounterweights. Various numbers and sizes of plates Itmay be employed in accordance with the magnitude and distribution of theweight required. The plates 16 are shown anchored in place byappropriate studs IT.

The crank 10 is supported and actuated from a shaft [8 through a block19 adjustably fixed in the opening I l and having a central hub 20 keyedor otherwise fixed to the shaft. In this instance the block I9 isarranged between a pair of heavy longitudinal guide ribs 2|, disposed atopposite sides of the opening II, and is provided with a pair of heavymarginal flanges 22 which seat against the ribs 2|- The block I9 isreleasably secured to the ribs 2| by bolts 23 projecting through theflanges 22 and through perforations 24 formed in the ribs. It will benoted that a series of perforations 24 is provided in each rib 2|,extending substantially throughout the length thereof, so that the blockl9 may be fixed in various positions within the opening II and therebyposition the crank pin M at various distances from the shaft [8. Theeffective length of the crank may thus readily be varied. It will alsobe noted that the perforations 24 are relatively small and closelyspaced so that an unusually fine adjustment of the effective cranklength is available.

It will be further noted that each adjustment of the effective length ofthe crank in the manner just described is accompanied by a correspondingadjustment of the counterweights l6 relative to the shaft l8. That is tosay, when the block I9 is in the upper end of the opening I I, asindicated in, Fig. 1, the effective length of the crank is increased toa maximum and the counterweights are at a maximum distance from theshaft l8; and when tween the block I9 and the crank [0 would result j jV tions of adjustment.

in severe wear. To avoid this, provision is made for uniting the blockl9 and crank l0 into a solid mass. In the crank shown this isaccomplished by inserting a wedge bar 26 between the block l9 and one ofthe ribs 2! in such manner as to securely clamp the block l9 between theribs 2|.

In this instance the bar 26 is drawn and secured in tight wedgingposition by a screw 21 threaded in an offset lug 28 at the small end ofthe bar and bearing against an end face of the block I9.

A tie plate 29, spanning the opening II in the crank l9, and secured inplace by the bolts 23,

serves to reinforce the crank structure against the spreading effectproduced by the wedge bar 26.

Provision is also preferably made for facilitating adjustment of thecrank l0 relative to the block Hi. In this instance a jack screw 39 isprovided for the purpose, the screw being threaded in the yoke l2 andarranged to bear against the end face of the block I9.

Adjustment of the crank Ill relative to the block i9 is best effectedwhile the crank is in the vertical position shown with itscounterweighted end I 3 below the block l9. With the screw adjusted intocontact with the block l9, the wedge 26 is loosened, the bolts 23 andplate 29 are withdrawn,

and the screw 30 then turned in a direction to raise or lower the crankI0 relative to the block l9 into the position desired. Then, whileretained in the adjusted position by the screw 39, the plate 29 andbolts 23 are reapplied and tightened, and the wedge bar 26 again drawntight between the block I9 and guide 2| by adjustment of the screw 21.The crank is then ready for operation.

Various changes may be made in the embodiment of the inventionhereinabove specifically described without departing from or sacrificingthe invention as defined in the appended claims.

I claim:

1. A rotary crank for driving oil well apparatus, said crank comprisinga member having an elongated opening formed therein and carrying aheavyma'ss'a' wrist pin carried by said member adjacent the-mass, asupporting block guided in said opening for adjustment relative to saidwrist pin, and means including bolts for releasably securing said blockto said member in various posi- 2. A rotary crank for driving oil wellappa- -ratus,,said crank comprising a member having an ing andadjustable longitudinally thereof to regulate the efiective radius ofthe crank, and means for'se'curin g-saidblock in various positions ofadjustment including means for wedging said block in said opening.

3. A rotary crank for driving oil well apparatus, said crank comprisinga member having an elongated opening formed therein and carrying a heavymass, a wrist pin carried by said member adjacent the mass, a supportingblock in said opening, screw means for adjusting said block in saidopening, and additional means for locking said block in variouspositions of adjustment.

4. A rotary crank for-driving oil well apparatus,'said crank comprisinga member having an elongated opening therein, a wrist pin carried bysaid member, guide ribs at the opposite sides of 'said opening, eachrib'having a longitudinal series of perforations therein, a supportingblock longitudinally adjustable in said opening and having'marginalportions seated upon said ribs, bolts in said marginal portionsprojecting through certainof said perforations to fix said block invarious positions of adjustment in said opening and Wedge means betweensaid supporting block and one of said guide ribs for tightening saidblock within said opening.

JOHN C. SLONNEGER.

